Improved IMC-filter design and IMC-PI equivalence: Application to quadrotor under gust of wind

Abstract

As known, internal model control is equivalent to a PI or a PID controller provided that the mathematical model associated to the process to be controlled is of first or second order respectively. So, to go beyond these particular cases and to make an extension in bringing more theoretical results, the article proposes a method to reach the equivalence between an internal model control and a PI controller regardless of the model order. To this end, the key idea consists of using a specific filter that exhibits superior robustness level compared to the classical filter and further leads to get a structure of a PI controller whatever the order of the model is. The developed procedure constitutes the main contribution of this article. To meet given set of specifications, the controller parameters are tuned through a straightforward analytic way using the dynamics of the tracking error. The proposed tuning strategy constitutes another contribution of the article. Furthermore, to evaluate the efficiency level of this procedure, an application to control an autonomous vehicle is described and the simulation results are shown to be satisfactory confirmed by a series of experimental tests.